Diacetyl (2,3-butanedione; C6H6O2) and trimellitic anhydride (“TMA”; 1,3-dihydro-1,3-dioxo-5-isobenzofurancarboxylic acid; C9H4O5) are toxic agents. Exposure to either may result in the development of respiratory illness or disease. Historically, optical detection and analysis of toxic agents has been more practical than other means for on-line continuous monitoring of hazardous levels because of the rapidity of the analysis. Optical detection and analysis of diacetyl has previously employed transitional metal complexes precipitated onto filters for visual inspection or applied to transparent films for ultraviolet-visible (“UV/VIS”) spectroscopy. However, transitional metal complexes are expensive, difficult to prepare, and not sufficiently durable for continuous monitoring applications in clinical or manufacturing settings.
At present, there are no practical methods of rapid, on-line, continuous monitoring of either diacetyl or TMA levels.
There is a need in the industry for optical sensors capable of detecting the presence of diacetyl, TMA, and other elements or compounds, that are more durable, less expensive, and easier to manufacture than the spectroscopic filters and films currently available.